John h



(No Model.)-

J. H. BRADLEY.

A BELT TIGHTENER.

Patented Aug 2-2, 1882.

UNITED STATES PATENT OFFICE.

JOHN H. BRADLEY, OF PHILADELPHIA, PA., ASSIGNOR TO BENJAMIN THAOKARA,CHARLES THAOKAR-A, AND A. M. THAOKARA, OF SAME PLACE, AND JOHN H.SOUTHWORTH, OF SPRINGFIELD, MASS.

B ELT-TIGHTENER.

SPECIFICATION forming part of Letters Patent No. 263,106, dated August22, 1882.

Application filed July 24, 1882. (N0 model.)

To all 'whom it may concern:

Be it known that I, JOHN H. BRADLEY, a

citizen of the United States, and a resident of Philadelphia,Pennsylvania, have invented certain Improvements in Belt -Tighteners, ofwhich the following is a specification. The object of my invention is toconstructa compact and convenient belt-tightener; and this object Iattain in the manner which I will now proceed to describe, referencebeing had to the accompanying drawings, in which Figure 1 is a side viewof my improved belttightener, and Fig. 2 afront view of the same.

A represents the shaft or spindle of a lathe, polishing-wheel, or otherdevice upon a workbench, B being an overhead countershaft, and D thebelt passing round a pulley, w, on the shaft B and a pulley, on theshaft A, as usual.

Owing to the high speed at which such tools as polishing-wheels are run,the lacings of an ordinary belt are rapidly worn out, and frequentstoppages for repairs become necessary, hence the use of a riveted beltand an automatic belt-tightener is advisable.

This belt-tightener Iconstruct in thefollowing manner: To theceiling-joists or other suitable support I secure a pair of hangers, aa, the lower ends of which are connected by a pin, b, and to this pin ishung a duplex bell-crank lever, 61, the short arm of which carries thespindle of a roll, c, which bears upon the belt D, the long arm of thelever having a bar,f, and to the latter is attached one end of a cord orchain, g, which passes round a pulley, h, hung to the ceiling, and hasat the other end a weight, m. The tendency of this weight is to elevatethe long arm of the lever 07, and thus cause the roll 6 to press uponthe belt D and keep the same tight. The action of the roll e is to pressthe belt away from the front of the bench, and thus lessen the risk ofthe said belt, coming in contact with and causing injury to the personworking at the bench.

When it is desired to throw the shaft or spindle A out of operation thelong arm of the lever d is depressed by means of a hooked rod adapted tothe bar f, the roll 0 being thereby moved away from the belt D, which isallowed to run slack.

By using two hangers and a duplex bellcrank lever, as shown, I amenabled to provide a firm support for the fulcrum-pin b, and for thespindle ot' the roll 0. The use of the duplex lever is not necessary,however, as a single lever and hanger may in some cases be used.

An important feature of my invention is the mode of hanging thebell-crank lever-that is to say, the location of thefulcrum at the frontof the pulley a: and the projection of the long arm of the lever to therear of the said pulleyfor by this means compactness is insured withoutlessening the leverage, the entire device being practically within thelateral limits of the work-bench, whereas a different mode of hangingthe lever would necessitate a considerable projection of the long arm ofthe same either in front or rear of the bench. It the arm projected infront of the bench said arm and the cord and weight connected theretowould inconvenience the person working at the bench, while theprojection of the arm at the rear of the bench would in most cases beimpossible, owing to the fact that work-benches are generally builtclose to the wall of the building in order to insure good light.

I claim as my invention- 1. The combination of the pulleys w and y andbelt D with a bell-crank lever having its long arm weighted and itsshortarm provided with a belt-pressing roll, 0, said lever being hung inrespect to the pulleys, belt, and bench as described, whereby its longarm is located over the bench, as set forth.

2. The combination of the pulleys a: y, belt D, hangers a, duplexbell-crank lever d, roll 8, and weight, as described.

Intestimon y whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

J. H. BRADLEY.

Witnesses:

JAMES I TOBIN, HARRY SMITH.

